Method and apparatus for conditioning water



1951 L. o. GUNDERSON 2;570,l15

METHOD AND APPARATUS FOR CONDITIONING WATER Filed July 6, 1946 5 Sheets-Sheet 1 Oct. 2, 1951 L. o. GUNDERSON METHOD AND APPARATUS FOR CONDITIONING WATER Filed July 6, 1946 5 Sheets-Sheet 2 Get. 2, 1951 GUNDERSQN 2,570,115

METHOD AND APPARATUS FOR CONDITIONING WATER Filed July 6, 1946 5 Sheets-Sheet 3 A? Eqjj 2 1 E ni 6/ /6 6 LEW/s 0. @wvo EBSO/V Oct. 2, N51 o. GUNDERSON METHOD AND APPARATUS FOR CONDITIONING WATER Filed July 6, 1946 5 Sheets-Sheet 4 g s; s s 8 e 63$ 8 e s a Q Q Mu mwo @0000 00mm% @Gooo ooo oowww [5741 5227 [UP A a w/ s 0. GuA/oEeso/v 1951 L. o. GUNDERSON 2,570,115

METHOD AND APPARATUS FOR CONDITIONING WATER Filed July e, 1946 5 Sh ets-Sheet 5 Patented Oct. 2, 1951 METHOD AND APPARATUS FOR CONDITIONING WATER Lewis 0. Gunderson, Park Ridge, IlL, assignor to Dearborn Chemical Company, Chicago, 111., a corporation of Illinois Application July 6, 1946, Serial No. 681,757

3 Claims. 1

This invention relates to a method and apparatus for eliminating foaming conditions in steam boilers.

Foaming of boiler water is not, as commonly thought, equivalent to an accumulation of foam on top of the surface of the boiler water. When steam is rapidly withdrawn from a boiler with resultant foaming, there is no water surface within the boiler correlated with the water level indicated in the conventional water glass attached to the boiler. In other words, there is no sharp line of demarcation between solid water and foam in a boiler during rapid steam withdrawal.

The foaming of boiler water is actually a rapid expansion of the water in the steam generating area of the boiler brought about by myriads of small steam bubbles that do not increase appreciably in size and do not coalesce to form large bubbles. As a consequence, the entire volume of water in the steam generating area is expanded by myriads of rising small steam bubbles until the thus formed so-called light Water may fill the steam space and become entrained with the steam leaving the boiler. actually due to the rapid formation of very large numbers of small steam bubbles that rise through the water without coalescing and Without growing appreciabl in size.

I have now found that foaming in boiler water may be prevented by inducing formation in the steam generating region of a relatively small number of relatively large bubbles rather than a relatively large number of relatively small bubbles. I have further found that such formation of relatively few large bubbles can be induced b establishing in the boiler water, at or near the boiler area utilized for heat transfer to the boiler water, a layer of superheated water of substantial depth or thickness and providin nuclei for steam generation in said layer adjacently or on the heat transfer surface. Large steam bubbles are formed in limited number more or less exclusively at these nuclei and rise through the layer of superheated water, and during such rise act as additional nuclei for additional steam generation so that superheated water is rapidly evaporated into such bubbles. As a result, the bubbles grow in size while rising through the superheated layer of water. Since nuclei for steam generation are provided in the superheated region of the boiler, steam generation occurs preferentially at these nuclei and into the bubbles rising from the nuclei, with consequent formation of few but large bubbles rather than a large number of small bubbles. Such boiling will prevent any abnormal Thus, foamin is I superheating of the body of boiler water and therefore minimizes the formation of numerous steam-generating nuclei in the boiler water, so that no foam formation will occur.

. The nuclei for steam generation provided according to the present invention in the superheated region of the boiler water preferably takes the form of one or more gas-water interfaces established at one or more localities, so that steam generation will occur into one or more gas pockets. The gas pockets may be established intermittently or more or less permanently. For instance, I may provide adjacently the heat transfer surface one or more inverted cup-like structures adapted to form steam pockets, or I may drop into the boiler a small number of ebullators (more or less irregularly configurated solid objects adapted to form air or steam pockets, or otherwise capable of acting as nuclei for the generation of steam), for instance, of spherical form and provided with indentations over all or part of their surfaces. I can also release or generate gases such as inert gases, nitrogen or hydrogen in the superheated boiler water region, or provide electrical heating means disposed in the superheated region to generate steam bubbles herein. Further, mechanically, electrically, or magnetically operated vibrators, means for forcing a stream of Water against a bafiling surface, or other cavitating means may be employed to establish internal cavities in the boiler region containing superheated water.

To confine the generation of steam to the nuclei provided as disclosed, I can incorporate with the boiler water hydrophilic substances, such as hydrophilic colloidal matter, that render the walls of the boiler as well as solid particles suspended or dispersed therein hydrophilic so as to lessen the capacity of the boiler Walls or the solid particles for acting as nuclei for steam generation. Such substances include tannins, alginates, gum arabic, lignin sulfonates and synthetic hydrophilic colloids. Boiler water containing surface tension-reducing agents, such as wetting agents, of course, inherently tend to foam, but when such tension-reducing agents, in particular, wetting agents, are employed as disclosed in the present application, these substances have the surprising effect of inhibiting foaming completely.

It is, therefore, an important object of the present invention to provide improved methods and apparatus for inhibiting foaming in boiler water having a natural tendency to foam.

Another important object of the present invention is to provide methods and apparatus for in- 3 hibiting foaming in boiler water involving the establishment of a layer of superheated water in a body of boiler water and selectively induce ing generation of steam bubbles at or near the bottom of said layer whereby evaporation is effected principally into seam bubbles with the result that the steam bubbles grow into large bubbles as they rise through the layer of superheated water.

A further important object of the present invention is to provide methods and apparatus for preventing foaming in boiler water involving the establishment of a layer of superheated water of substantial depth in the body of boiler water, providing one or more gas pockets at or near the bottom of said layer of superheated water, and affecting evaporation into said gas pockets with resultant formation of steam bubbles that grow into large size on rising through the layer of superheated water after breaking away from the gas-water interface. H

Other and further objects and features of the present invention will become apparent from the following description and appended claims as well as from the attached drawings which show, diagrammatically and by way of examples, several types of apparatus and methods according to the present invention. More particularly:

Figure 1 is a fragmentary vertical longitudinal cross-sectional view, with parts shown in elevation, through a locomotive boiler equipped with a device according to the present invention;

Figure 2 is a front elevation of the structure shown in Figure 1;'

Figure 3 is a greatly enlarged transverse crosssectional view through the foam inhibiting device in the locomotive boiler of Figure 1;

Figure 4 is a greatly enlarged fragmentary side elevation of the device shown in Figure 3;

Figure 5 is a greatly enlarged transverse vertical cross-sectional view through another foam inhibiting device capable of being substituted for that shown in Figures 3 and 4;

Figure -6 is a greatly enlarged fragmentary side elevational view of the device of Figure 5-;

Figure '7 is a view similar to Figure 2 showing a device similar to that shown in Figures 3 and 4 disposed in the locomotive boiler in a slightly different manner;

Figure 81s a vertical transverse cross-sectional view through a locomotive boiler similar to the boiler shown in Figure l, but equipped with another foam inhibiting device according to the present invention, the view of Figure 8 being taken along the line VIII-VIII of Figure 1;

Figure 9 is a fragmentary horizontal longitudinal cross-sectional view through a locomotive boiler similar to that shown in Figure l but equipped with another foam inhibiting device according to the present invention, the view of Figure 9 being taken along the line IXIX of Figure 1; t

Figure 10 is an end elevational view of the structure shown in Figure 9;

Figure 11 is a greatly enlarged vertical crosssectional view through one of the foam inhibiting devices shown in Figures 9 and 10 Figure 12 is an end elevation similar to Figure 2 showing a locomotive boiler provided with still another foam inhibiting device according to the present invention;

Figure 13 is a fragmentary horizontal crosssectional view of the boiler of Figure 12 similar to the view of Figure 9;

Figure 14 'is a greatly enlarged fragmentary 4 vertical cross-sectional view taken along the line XIVXIV of Figure 12;

Figure 15 is a vertical cross-sectional view through a stationary boiler equipped with foam inhibiting devices according to the present invention;

Figure 16 is a greatly enlarged cross-sectional view through one of the foam inhibiting devices of Figure 15;

Figure 17 is a greatly enlarged fragmentary cross-sectional view through one of the foam inhibiting devices and through the crown sheet of the locomotive boiler shown in Figures 18 and 19;

Figure 18 is a view similar to Figure 2 showing a locomotiveboiler equipped with still another foam inhibiting device according to the present invention;

Figure 19 is a view similar to Figure 9 showing the boiler of Figure 18;

Figure 20 is a view similar to Figure 2 showing a locomotive boiler equipped with still another foam inhibiting device according to the present invention;

Figure 21 is a view similar to Figure 9 showing the boiler of Figure 20 in horizontal cross section;

Figure 22 is a view similar to Figure 2 showing a locomotive boiler equipped with still another foam inhibiting device according to the present invention;

Figure 23 is a view similar to Figure 9 showing the boiler of Figure 22 in horizontal cross section;

Figure 24 is a side elevational view, with parts broken away, of the tube and drum system of a conventional Stirling boiler equipped with a foam inhibiting device according to the present invention;

Figure 25 is a greatly enlarged fragmentary longitudinal cross-sectional view through one of the tubes. of the boiler of Figure 24; and

Figure 26 is a greatly enlarged cross-sectional view, with parts shown in elevation, of the foam inhibiting devices shown in Figures 24 and 25.

The locomotive boilers shown in Figures 1, 2,

- 7, 3, 9, 10, 12, 13, 18, 19, 20, 21, 22 and 23 are of conventional construction, apart from the foam inhibiting devices illustrated, and include a tubular boiler generally indicated by the reference numeral I0 having a conventional arrangement of tubes l3 and provided with a dome l4 having the usual dry pipe IS. A portion l6 of the fire box of the boiler has been illustrated in certain figures, and also the drainage outlet I! in the lower portion of the boiler. The crown sheet and stay bolts associated with the boilers are indicated, respectively, by the reference numerals l8 and IS. The side sheets are shown at 20. The water level is indicated by a broken line 2|. Since these various features are uniform throughout the different figures, the same reference numerals have been used in all the figures showing locomotive boilers.

Referring now to Figures 1 and 2, it will be noted that a plurality of bars or rods 25 are disposed on the crown sheet l8 to rest thereon between the stay bolts l9 lengthwise of the boiler. As best shown in Figures 3 and '4, the rods 25 are provided on their surfaces with a plurality of spaced conical indentations 26. These indentations preferably have at least their inner ends of capillary size and serve to establish immediately above the crown sheet a plurality of steam or air pockets that act as nuclei for the generation of steam bubbles. These rods 25 are preferably spaced from the crown sheet (say, by about onequarter inch) and from each other by -collars or washers 21. The crown sheet I8 is maintained hot enough to establish thereabove a layer of superheated water of substantial depth, preferably deeper than the thickness of the rods 25. The steam bubbles preferentially generated with the indentations 26 as nuclei rise through this superheated layer of water and in so rising serve to promote evaporation of additional steam into the steam bubbles, with resultant growth of the latter. The steam bubbles rising to the water level 2| are relatively few in number, due to the restricted number of indentations 26, and are also rather large due to growth by evaporation of additional steam thereinto. These bubbles therefore do not cause foaming.

In place of the rods 25, I may also utilize rods illustrated in Figures 5 and 6 and characterized by longitudinal grooves 3| that act as nuclei for the generation of steam similarly to the indentations 26 of the rods 25. The rods 30 are spaced from the crown sheet and from each other by collars or washers 32. It will be noted that in both types of rods or bars, the indentations 26 as well as the grooves 3| act as nuclei for the generation of steam by providing spaces or pockets wherein air or steam may accumulate to define a gas-water interface.

In Figure 7, I have illustrated a locomotive boiler provided with bars constructed identically as the bars 25, except for the omission of any collars or washers. Instead of being laid on the crown sheet, as are the bars 25, the bars 35 are held a fraction of an inch above the crown sheet 18 by suitable means, such as clamps 36 attached to the lower ends of the stray bolts l9. The bars 35 are indented similarly to the bars 25 and perform the same function. It will be noted that the bars 35 provide gas pockets at the bottom of the superheated water layer immediately above the crown sheet where the rate of heat transfer is rapid.

In Figure 8, other means for establishing gaswater interfaces in a superheated region of a body of boiler water are shown. There the two topmost rows of boiler tubes l3 are provided on their sides with longitudinal downwardly directed fins 40 each defining in combination with the boiler tube a narrow steam space adapted to function similarly to the indentations or grooves in the bars 25, 30 and 35.

In Figures 9, 10 and 11 I have shown still other means for establishing gas pockets in a superheated layer of boiler water that take the form of inverted cup-like members 45. Certain of these cup-like members are held a fraction of an inch or so above the crown sheet l8 by means of bars 46 extending lengthwise of the boiler between the stay bolts IS with their ends attached to transverse bars 41 which, in turn, have their ends affixed to the inside of the boiler. Other cup-shaped members 45 are suspended along the upper portion of the side sheets 20 by means of bars 48 extending lengthwise of the boiler and having their ends afiixed to transverse bars 49 having their ends attached to the side sheet and to the sides of the boiler. The inverted cup-like structures 45 are adapted to hold air or steam, and evaporation takes place into the pockets defined by these cup-like structures that serve as nuclei for steam generation; The steam bubbles break off from the lower edges of the cup-like structures 45 and rise through a layer of super- 6 heated water established immediately abbv the crown sheet l8 and at the sides of the upper parts of the side sheet 20, with the result disclosed hereinabove.

It is also possible, as shown in Figures 12, 13 and '14, to provide a crown sheet I formed with a plurality of downwardly directed conical indentations 50 preferably terminating in capillary spaces that will serve as nuclei for steam generation due to capillary retention of air or steam, and to bring about particularly effective heat transfer into the spaces defined by the indentations 50 by reason of the increased surface available for heat transfer. Steam generation tends to be localized at the indentations 50, so that relatively few steam bubbles rising therethrough and growing due to evaporation while passing through the superheated layer of water immediately above the crown sheet will not induce foaming.

A gas-water interface may also be provided by means shown in Figures 17, 18 and 19, and including a series of tubes 66 disposed lengthwise of the boiler, over the crown sheet l8 and along the side sheets 20 and provided with spaced bottom apertures 6|. The tubes may suitably be supported by legs 62. A gas such as hydrogen, nitrogen or other gas insoluble in water, is fed to the tubes 60 through a branched tube 63 connected to one set of ends of the tubes 60. The other ends of tubes 60 are preferably closed. The gas may be supplied to the tube 63 from any suitable source (not shown) such as a tank carried on the locomotive outside the boiler. The tubes 60 are preferably quite small having, for instance, a diameter of one-quarter inch, and the apertures 6! may have a diameter such as one-thirty-second inch. The rate of flow of gas through the tube 23 into the tubes 60 is preferably such as to permit the escape of gas through the apertures 6|. In this case, the rising gas bubbles provide for the evaporation of steam into the gas bubbles as the latter rise through the superheated layers of water immediately above the crown sheet and along upper parts of the side sheets. The gas bubbles will, therefore, grow in size during their passage through the layer of superheated water, so that the large bubbles breaking on the surface of the boiler water will not induce foaming.

In Figures 20 and 21, I have shown still other means for providing gas-water interfaces in a superheated region of a body of boiler water. As shown, pairs of positive electrodes 65 and negative electrodes 66 are disposed lengthwise of the locomotive boiler a fraction of an inch above the crown sheet l8 between the stay bolts l9. The anodes 65 are energized by means of a conductor or lead wire 61 entering into the boiler through a plug of insulating material 68. The cathodes 66 are likewise energized by means of a lead wire 69 entering into the boiler through an insulating plug 10. Insulating clamps H hold the electrodes spaced from one another, from the crown sheet, and from the stay bolts. The bubbles of oxygen and hydrogen rising from the anodes 65 and the cathodes 66 grow in size as they rise through the layer of superheated water immediately above the crown sheet due to evaporation into the bubbles. The relatively few rather large steam containing bubbles thus formed do not induce foaming.

Figures 22 and 23 show other means for providing gas-water interfaces in a superheated @region -of a body ofsboiler -water. theseil'fiez.ures, "a Irhave show-nae. .-resistance wire 2 15, such rasiaNichrcme disposed. over the crown sheet .I 8,

a fraction of an inch thereabove lengthwise. of

Ethel :boiler :;,bet.ween aStay .zbolts I 9 sand. attached I :the etwby'meansiof insulating. clamps" 16. .This el ctrical es stor 5 is energiz yamean of r eleedt ir l senter ne and coolin out. r m th boiler through an electrically: insulated; plug 18. fifteam ,;ge nerated around the heating element 35 {provides a gasewaterinterface from ,which steam bubbles break awayand rise through a superheatedlayer. ofboiler water. ,During, such rise,- the: steam bubbles increase insize dueto evaporation into-the...steam.bubblesjrom the superheated water. Relatively few .but large steam; h h lesareo thus formed that do not induqeiiqamineof the means for establishinggas-water interfaces in the vicinity of a locomotive firebox illustrated in Figures 1 to 14 andl'l to 23 may also be provided in the vicinity of the boiler tubesof a locomotive, if desired or necessary to more completely inhibit foaming. V -In Figure I have-shown a stationary'ver- "ticalboiler 80 set in brickwork'or the like 8! providing a fire box 82 below the boiler having agrate 83 adapted to hold solid fuel. Flues 84 are formed in the brick work around the lower sides of the boiler, which is provided with a steam pipe 85. Meansfor preventing'foaming -take the'form of a plurality-of small spheres. or pellets or relatively small bodies 98 (see Figure 16) --provided on their surface with spaced -minute indentations 9| preferably terminating inwardly in capillary spaces. These pellets 90 may-be dropped into the boiler 89 so as to rest on the bottom of the boiler. The minute in- -denations 9! on the febullators 90 serve to prevent foaming by the generation of large steam bubbles in the manner explained hereinabove.

:Anyof the means for establishing gas-water interfaces described in connection with locomotive boilers and illustrated in Figures 1 to 14 and 17* to 23-may be employed in a stationary boiler to minimize or prevent foaming.

In Figures-Ziand '25 I have shownthe tube and drum system of a conventional-Stirling type steam boiler. The feed water tubes are indicated by the reference numeral I00, the tubes wherein steam rises by the reference numeral .IEH, and the drums by the reference numeral 102. In the tubes are disposed relatively deep inverted cup-like structures ,1 05 (see Figure 2.6)

ghaving theirbottoms pierced as at I06 .to receive and .fitstightly over wires H]? on which a plu- --rality of suchcup-like memberslfili are threaded. Collars mean the wire I01 abut the two sides of ;the.bottoms of the members 110.5, toihold the -members H35 on the wirepand -to insureicomplete closure and sealing of the apertures IE6. Each tube 108 is provided with-a wirelfll-having a plurality of inverted cup-like structures [05 attached thereto. The upper end of the-wire projects into an upper drumand is there attached "to suitable means, such as a cross bar I03, while-the lower ends project into the lower .drum for attachment to a cross bar 109. As :shown in Figure.25, -the inverted cup-like structures are deep enough to provide ,gas pockets even at the bends or curves of the-tubes H30.

The inverted cup-like-structure's I05 serve as nuclei for steam generation and prevent spasmouic, eruptive boiling within the tubes HIE! ',-wh1 cnotherwise would-occur when. the tubes I99 mares-filled LWith: superheated :water i and resultin .columns .of. superheatedcwater-am :suddenlyzdis- --place-d ;up.war.dly by: the. formation inor. entrance -.of steam bubbles into said tubes.

it will: thusgbe seenithat .I h'ave provided a pmethod foreliminating foaming in thegenera- .tion of -steam fromiwateri including the.- stepsof transmitting heat..to the -.water at such rate-.as establish and maintain in. the body of .water being heated a definite layer of superheated steam ,of ,quite. substantial depth and also providin nuclei for preferentialsteam, generationat ornear the" bottom .of the layerofsuperheated water. These nu'cljei preferably providesmaller or larger gas pockets defining. gas-water interfaces. Steam evaporates into the gas pockets, with the result that-steam containing bubbles break away from the "gas-water interface and" rise through the-body-of boiler water. 'Duringtheir rise 'through the superheated layer of boiler water, evaporation "from the superheated "water intm'therising' bubbles "takes place, so that the lattengrow' in:size,:.with the result that relatively 'fewbut relativelylarge steam-containing bubbles riseto .the surface of the water and break there.

.' In ;order1.to; eliminate or. reduce thef formation of v:steam :bubbles rat other 1 localities than the above-mentioned: nuclei, :.I:-:may, tand'rpreferably do, incorporate with the :watera hydrophilic .substance, in particular, a hydrophilic :colloid .such as .sodium 1 alginate, tannin, ,lignin, 1 sulfon- -ate,,redwood.bark dust extract, :gum arabic, or the like. Thesehydrophilic materials serveto induce morecompletewetting of the boiler walls and .of any solid particles suspended therein,,-so that the,;bo i1er wallsand.suchsuspended partic1es do,not.tend;to act as nucleifor the generationpf steam. .lsim'ilarresults may be obtained byincorporation with the boiler water of sur- 'face=tension.reducing substances such as ordinarysoaps, Aerosol'OT (dioctyl ester of sodium sulfosuccinic *acid), Aresket (monobutyl diphenol sodium monosulfonate), Igepon 'T" (C11I-I33CONHC2H4SO3Na) or the like. When wettingagents'such' as those-disclosed are" added to *water' in small-amounts,- such as less "than" 500 parts per-million, theireffect is 'principallyto :reducedirectly the surface tension of the water. WhenJa'dded 'in larger :amounts, such wetting agents are vbelieve'd to Iform micelles that are highly:hydrcphilic;.and.tendto absorb or cap- :ture. hydrophobic materials dispersed or suspended in the boiler water, such. as hydrocarbon oils, therebyrreducinseor eliminatin undesir d n c1 i for steamigeneration. In such higher concentrations, where m-icellefor-mation is believed to takeplace, the surfaceactivity of the wetting agent is. believedto decrease.

,Inbrief, the. action ofthe mechanical devices illustratedanddescribed hereinabove can be and preferably .is reinforced by incorporating with boiler atersurface tension reducing agents, in particular, .wetting agents, so that the water will wet the boiler walls as wellas any hydrophobic solid or'liqui'd particles suspended or dispersed therein, with the result that the tendency for any part "of the-boiler wall or 'for any solid or liquid -matter suspended or dispersed in the boiler'water-to-function-as nuclei for'steam generation is reduced or eliminated. Many-boiler waters have a natural tendency to foam, due to a .content .of surface tension reducing agents, whichinherentlyztendto produce foaming. The methods of .thepresent invention are particularly applicable .to:the;preventi0n of foaming in such boiler waters. Y

When boiler water contains a relatively large amount of surface tension reducing agents, either due to accumulation of such agents (derived from the feed water or from lubricating oil or from contamination) or due to deliberate addition of surface tension reducing agents, the whole body of boiler water may become superheated, since then nuclei for steam generation such as suspended solid particles or irregular parts of the boiler surface have been rendered hydrophilic and hence inactivated as nuclei for steam generation. The gas-water interfaces provided according to the present invention are particularly adapted to function as nuclei for steam generation in such wholly superheated waters, since the gas-water interfaces are not inactivated by hydrophilic agents as are the surfaces of suspended solid particles or parts of the boiler walls. It should further be noted that when the whole body of boiler water has become superheated, then even somewhat hydrophilic solid particles or areas of the boiler walls may function as nuclei for steam generation, with the resultant formation of a large number of small bubbles and consequent foaming. However, the provision of gas-water interfaces according to the present invention will lessen substantially the tendency of the whole body of boiler water to become superheated, so that the tendency of the boiler water to foam is reduced or eliminated.

In other words, the gas-water interfaces provided according to the present invention and the means above disclosed for establishing or generating such gas-water interfaces are particularly adapted to prevent or reduce foaming in boiler waters that are or have been made more hydrophilic due to accumulation therein or addition thereto of surface tension reducing agents or agents that otherwise tend to eliminate steam generating nuclei normally functioning in the boiler water. Such hydrophilic boiler waters as well as boiler waters devoid of nuclei for steam generation have a natural tendency to foam which is reduced or eliminated by the means described hereinabove for establishing gas-water interfaces in the boiler water.

As illustrated by specific examples described hereinabove, the means disclosed in the present invention for establishing nuclei for preferential localized steam generation can be provided in many forms, including means defining small preferably capillary spaces either in the water side of the heat transmitting boiler wall or in other structures in the immediate vicinity of the heattransmitting boiler walls, independently heated means disposed in the boiler in the immediate vicinity of the heat-transmitting boiler walls, means for generating or releasing or exposing gases insoluble in water in the boiler in the immediate vicinity of the heat-transmitting boiler walls, or the like.

It should be understood that many details of construction, composition, and method may be varied within a wide range without departing from the principles of this invention and without sacrificing the advantages disclosed hereinabove, and it is, therefore, not my purpose to limit the patent granted on this invention otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. For the prevention of foaming in a steam boiler having a boiler wall part utilized for heat transfer to a body of boiler water contained in said boiler, the combination with said boiler wall part of a plurality of bars disposed in the immediate vicinity of said boiler wall part and formed with indentations capable of forming gas pockets in a layer of superheated Water established and maintained immediately above said boiler wall part, said gas pockets being adapted to function as nuclei for the generation of steam bubbles which on rising through said layer of superheated water will provide for the evaporation of additional steam.

2. In a steam boiler having a boiler wall part utilized for heat transfer to a body of water contained in said boiler, the combination with said boiler wall of a plurality of bars disposed in the immediate vicinity of said boiler wall part, said bars being formed with longitudinal grooves capable of forming gas pockets in a layer of superheated water established and maintained immediately above said boiler wall part, said gas pockets being adapted to function as nuclei for the generation of steam bubbles which on rising through said layer of superheated water will provide for the evaporation of additional steam.

3. In a steam boiler having a boiler wall part utilized for heat transfer to a body of boiler water contained in said boiler, the combination with said boiler wall part of a plurality of bars disposed in the immediate vicinity of said boiler wall part, said bars being formed with spaced conical indentations capable of forming gas pockets in a layer of superheated water established and maintained immediately above said boiler wall part, said gas pockets being adapted to function as nuclei for the generation of steam bubbles which on rising through said layer of superheated water will provide for the evaporation of additional steam.

LEWIS O. GUNDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 787,941 Phillipe et al. Apr. 25, 1905 1,579,454 Neeley Apr. 6, 1926 1,940,070 Barry et a1. Dec. 19, 1933 2,320,366 Leaf June 1, 1943 2,438,929 Leaf Apr. 6, 1948 2,439,797 Denman Apr. 20, 1948 2,449,656 Kell Sept. 21, 1948 2,469,450 Bird et al May 10, 1949 OTHER REFERENCES Gattermann: The Practical Methods of Organic Chemistry, page 30 (1896 edition).

Arny: Principles of Pharmacy, pub. 1926, pages 100, 101 and 104.

Eldridge: College Physics, pub. 1937, page 242.

Morton: Laboratory Technique in Organic Chemistry. Pub. 1938, pages 104 and 105. 

1. FOR THE PREVENTION OF FOAMING IN A STEAM BOILER HAVING A BOILER WALL PART UTILIZED FOR HEAT TRANSFER TO A BODY OF BOILER WATER CONTAINED IN SAID BOILER, THE COMBINATION WITH SAID BOILER WALL PART OF A PLURALITY OF BARS DISPOSED IN THE IMMEDIATE VICINITY OF SAID BOILER WALL PART AND FORMED WITH INDENTATIONS CAPABLE OF FORMING GAS POCKETS IN A LAYER OF SUPERHEATED WATER ESTABLISHED AND MAINTAINED IMMEDIATELY ABOVE SAID BOILER WALL PART, SAID GAS POCKETS BEING ADAPTED TO FUNCTION AS NUCLEI FOR THE GENERATION OF STEAM BUBBLES WHICH ON RISING THROUGH SAID LAYER OF SUPERHEATED WATER WILL PROVIDE FOR THE EVAPORATION OF ADITIONAL STEAM. 